Bridges

Cover of Fatigue and Maintenance Aspects of a Welded Steel Truss Railway Bridge
Fatigue and Maintenance Aspects of a Welded Steel Truss Railway Bridge
  • Publication no: ABC-MAR023-11
  • Published: 31 October 2011

The main structural components of the railway bridge at Bankstown, installed in January 2011, are two 18m steel welded arch trusses with an overall height of 3.5m. Each truss comprises fabricated box sections for the chords and I sections for the hangers and diagonals (except for the hanger at each end). Curved transitions between the chord side plates and the flanges of the hangers and diagonals, in addition to optimised weld configurations, are provided to improve fatigue performance.

The structural performance of a welded structure operating under a large number of alternating live load stresses is dependent to a large extent on the design (including structural configuration, member sizes, connection transitions and welding details), fabrication (welding quality control) and asset management (inspection and maintenance plan).

These aspects are covered in this paper for the railway bridge at Bankstown where a range of experts including bridge design engineers, welding engineers and materials specialists was involved during the design and fabrication stages of the arch trusses. In addition, some elements of fatigue design, including life enhancement by weld toe grinding, S-N curves and fatigue damage ratio, are discussed.